Nori has a heteromorphic alternation of generation (i.e. the generations are different in shape and size), alternating
between the foliose gametophyte blade (male/female) and the microscopic filamentous sporophyte
known as the conchocelis phase. The conchocelis phase bores into oyster shells and upon maturation releases
conchospores, which grow into blades (Sahoo & Yarish, 2005). Conchocelis can also be cultured “freeliving” in
laboratory settings (He & Yarish 2006). The life history of Porphyra umbilicalis was first characterized by Kathleen
M. Drew in 1949 when she noted that the previously described “Conchocelis rosea” was not a separate
species but simply a phase in the life cycle of P. umbilicalis. This discovery led to the establishment of nori seaweed
aquaculture industry in Japan where Kathleen M. Drew is known as the “Mother of the Sea”.